Neutrophil-activating Peptide-1/Interleukin 8 (NAP-1/IL-8) is a novel cytokine that activates neutrophils. It was first identified as a monocyte-derived neutrophil chemotactic factor (MDNCF) and later named NAP-1/IL-8. This peptide is secreted by various cells in response to inflammatory stimuli and is involved in neutrophil recruitment and activation. NAP-1/IL-8 shares structural and functional similarities with other chemotactic peptides such as C5a and f-Met-Leu-Phe, but it is more selective in its effects, primarily acting on neutrophils. It induces a range of neutrophil responses, including shape change, adherence, directed movement, enzyme secretion, and the respiratory burst. NAP-1/IL-8 activates neutrophils through a signaling pathway involving GTP-binding proteins, phosphatidylinositol hydrolysis, and calcium mobilization. It is also involved in various inflammatory diseases, including psoriasis, arthritis, and lung conditions like idiopathic pulmonary fibrosis and asbestosis. NAP-1/IL-8 is produced by multiple cell types, including monocytes, fibroblasts, epithelial cells, and hepatocytes, in response to inflammatory signals such as IL-1 and TNF. Its widespread expression suggests it may act as a universal neutrophil attractant during tissue inflammation. NAP-1/IL-8 has potential therapeutic applications as an anti-inflammatory agent, targeting its signaling pathways.Neutrophil-activating Peptide-1/Interleukin 8 (NAP-1/IL-8) is a novel cytokine that activates neutrophils. It was first identified as a monocyte-derived neutrophil chemotactic factor (MDNCF) and later named NAP-1/IL-8. This peptide is secreted by various cells in response to inflammatory stimuli and is involved in neutrophil recruitment and activation. NAP-1/IL-8 shares structural and functional similarities with other chemotactic peptides such as C5a and f-Met-Leu-Phe, but it is more selective in its effects, primarily acting on neutrophils. It induces a range of neutrophil responses, including shape change, adherence, directed movement, enzyme secretion, and the respiratory burst. NAP-1/IL-8 activates neutrophils through a signaling pathway involving GTP-binding proteins, phosphatidylinositol hydrolysis, and calcium mobilization. It is also involved in various inflammatory diseases, including psoriasis, arthritis, and lung conditions like idiopathic pulmonary fibrosis and asbestosis. NAP-1/IL-8 is produced by multiple cell types, including monocytes, fibroblasts, epithelial cells, and hepatocytes, in response to inflammatory signals such as IL-1 and TNF. Its widespread expression suggests it may act as a universal neutrophil attractant during tissue inflammation. NAP-1/IL-8 has potential therapeutic applications as an anti-inflammatory agent, targeting its signaling pathways.